1. BGRIMM Magnetic Materials & Technology Fuyang Co. Ltd., Fuyang 236000, Anhui,China 2. National Engineering Research Center for Magnetic Materials, Beijing 102600, China
Abstract:The preparation of Co- Ni alloyed fine particles by the oxidation- reduction process has the characteristics of simple process, the reaction and the particles diameter can be controlled. The influence factors about particles shape, particles diameter and the particles distributing were studied. The results showed the higher the concentration of reactants, the smaller the particle size, the more serious the agglomeration and the worse the uniformity of powder distribution. The type of reducing agent will affect the composition of the sample. Choose KBH4 as reducing agent. Because that oxidation- reduction reaction is violent, the particle size of the produce powder is relatively fine. The fine powder is easily oxidized to metal oxide in air, losing ferromagnetism of alloy. Choose hydrazine hydrate as reducing agent. The prepared Co- Ni alloyed fine particles have typical soft magnetic characteristics. The particle size of the powder is 0. 7- 0. 8μm. Ms=0. 69MA/m, Br=0. 07MA/m, Hc=7. 24kA/m.